FINE-TUNE GOALS WITH ARTIFICIAL INSEMINATION

by: heather Smith Thomas

A growing number of commercial cattlemen as well as seedstock producers are experiencing the benefits of AI--for herd improvement, and to increase the profitability of the calves they sell. With AI, the stockman has access to a greater selection of bulls, for various goals in heifer production or steers to market. AI is the primary way that beef producers increase their progeny from superior sires.

During the past two decades there have been advances in AI, particularly in utilizing heat-synchonization drugs so that a group of cows or heifers can all be bred at one time (reducing the labor of heat-detection during breeding season). “Beyond that, there isn't a lot that's new in AI, in terms of the way we are doing things,” says John Hall, PhD (Extension Beef Specialist, University of Idaho, Superintendent of the Nancy M. Cummings Research, Extension and Education Center).

For the AI projects at this research ranch, the ranch crew continues to work with the Beef Reproductive Task Force and the Reproductive Leadership Team. “The Task Force is a consortium of those of us who do beef reproduction at various universities, doing research on estrous synchronization and AI. The Leadership Team is the consortium of representatives from the Task Force, along with representatives from AI studs, the pharmaceutical industry, and veterinarians. That's the group that came up with the recommended estrous synchronization protocols to use for AI—the recommendations you'll find in the back of the AI catalogs,” explains Hall.

“Basically what we do is work together, looking at the research from all the universities, on the different AI systems. When one of them looks promising, we analyze the data together to see if we have enough animals/numbers for valid conclusions, and whether it is consistent enough to say it's better than what we were doing before. We ask various questions, such as are we keeping the number of trips through the chute down to as few as possible? That's one of our objectives—no more than three trips through the chute, which includes the actual insemination,” he says.

“We look over all the data and then make the decision as to whether this is something we want to put on that list of recommended protocols. We also decide whether we want to take something off the list. There's a limit to how many protocols we put on that list,” says Hall. The group tries to select only the ones that are best for the cattle and for the people doing the work.

“The Leadership Team tries to choose the methods that are the most consistent and the most effective, for those groups of cattle. We also look at cost,” he explains.

“The beef industry hasn't really gone to quarter cc straws yet, even though we've talked about this. We are still using half cc straws. The AI studs continue to work on different extenders that they put with the semen. If they feel a different extender is working better, they'll change. We at the universities may be involved in helping with blind studies on things like that,” says Hall.

“In beef AI, we are still trying to increase the number of cows that get bred AI. One of the ways we've been doing this is though Applied Reproductive Strategy meetings. These focus on utilizing AI in both commercial and purebred herds. We are going to host one of these meetings here in Idaho September 30-October 1, 2011. This will be held in Boise,” he says. There will be a similar meeting in Missouri August 31-September 1, 2011.

“What we've seen recently as we've looked at the fixed-time AI systems (synchronizing and breeding the entire group at one time), is that we've made a lot of progress on the ability to successfully AI post-partum beef cows,” says Hall. In the past, the heat-synch protocols were mainly used on heifers.

“It seems like we've hit a wall with heifers at about 55 to 60 percent AI pregnancy rates in commercial herds. We are not really sure why. Now, in the post-partum cows we are seeing 55 to 65 percent in many of our large-scale studies that have been done with producers. I am conservative, telling producers that they shouldn't expect more than 50 to 55 percent, although many will do better than that.”

Hall says the big keys for AI now are management issues. “Those cows need to be in good body condition score (5 or better). They need to be at least 30 to 40 days post-partum, before you start a synchronization program,” he says. If a cow is too thin, or has not recovered enough from calving, she is not going to conceive -- and response to the money and effort you put into a synchronization program will be disappointing.

One of the big shifts recently in AI is more use of fixed-time breeding — breeding all the cows on a single day. This makes it more feasible for many operators to do it, rather than spending the time and expense of heat-detection and breeding cows daily through the breeding season. “It's more feasible to do it all on one day, in terms of labor and success, and lining up technicians,” says Hall.

In any herd, the risky cattle to get successfully bred with AI are the young cows, preparing for their second and third calves. They can be a challenge because they are still growing and also putting so much energy into feeding their present calf that they may be slow to cycle.

“Many of the programs we use that include CIDRs really help those cows, because this does induce them to cycle. One of the things that we see—when people have been doing AI and estrus synchronization over a number of years—is the calving season becoming tighter, with more cows breeding in the desired time frame. Even the cows that conceive to natural service (by the clean-up bulls) are conceiving earlier in the breeding season, with use of the CIDRs and synchronization protocols,” he says. This can even help cows breed up more quickly in a program that depends on natural service rather than utilizing AI.







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